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Posted to commits@stanbol.apache.org by "Andrea Nuzzolese (JIRA)" <ji...@apache.org> on 2011/06/09 15:57:58 UTC

[jira] [Created] (STANBOL-222) Timeout exception from LOD remote endpoints when performing queries with the Entity Hub.

Timeout exception from LOD remote endpoints when performing queries with the Entity Hub.
----------------------------------------------------------------------------------------

                 Key: STANBOL-222
                 URL: https://issues.apache.org/jira/browse/STANBOL-222
             Project: Stanbol
          Issue Type: Bug
          Components: Entity Hub
            Reporter: Andrea Nuzzolese


The sparql constructs serialized by the Entity Hub that is used for querying remote LOD endpoints contain OPTIONAL patterns that require too much time to be evaluated.
An example is the following

CONSTRUCT { ... }
WHERE {     
	{ {?id <http://www.w3.org/2002/07/owl#sameAs> <http://www4.wiwiss.fu-berlin.de/factbook/resource/United_States> }}    
	 { OPTIONAL { ?id <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?v_1 . } }   
	 { OPTIONAL { ?id <http://www.w3.org/2000/01/rdf-schema#label> ?v_2 . } } 
}  
...

The sparql engine tries to satisfy the optional clauses in the whole graph ignoring the first condition ?id <http://www.w3.org/2002/07/owl#sameAs> <http://www4.wiwiss.fu-berlin.de/factbook/resource/United_States>

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[jira] [Commented] (STANBOL-222) Timeout exception from LOD remote endpoints when performing queries with the Entity Hub.

Posted by "Rupert Westenthaler (JIRA)" <ji...@apache.org>.
    [ https://issues.apache.org/jira/browse/STANBOL-222?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13046862#comment-13046862 ] 

Rupert Westenthaler commented on STANBOL-222:
---------------------------------------------

see http://markmail.org/thread/jbsvj23mtyqe726z for details and how to re-formulate queries to improve query performance.

> Timeout exception from LOD remote endpoints when performing queries with the Entity Hub.
> ----------------------------------------------------------------------------------------
>
>                 Key: STANBOL-222
>                 URL: https://issues.apache.org/jira/browse/STANBOL-222
>             Project: Stanbol
>          Issue Type: Bug
>          Components: Entity Hub
>            Reporter: Andrea Nuzzolese
>
> The sparql constructs serialized by the Entity Hub that is used for querying remote LOD endpoints contain OPTIONAL patterns that require too much time to be evaluated.
> An example is the following
> CONSTRUCT { ... }
> WHERE {     
> 	{ {?id <http://www.w3.org/2002/07/owl#sameAs> <http://www4.wiwiss.fu-berlin.de/factbook/resource/United_States> }}    
> 	 { OPTIONAL { ?id <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?v_1 . } }   
> 	 { OPTIONAL { ?id <http://www.w3.org/2000/01/rdf-schema#label> ?v_2 . } } 
> }  
> ...
> The sparql engine tries to satisfy the optional clauses in the whole graph ignoring the first condition ?id <http://www.w3.org/2002/07/owl#sameAs> <http://www4.wiwiss.fu-berlin.de/factbook/resource/United_States>

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[jira] [Resolved] (STANBOL-222) Timeout exception from LOD remote endpoints when performing queries with the Entity Hub.

Posted by "Rupert Westenthaler (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/STANBOL-222?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Rupert Westenthaler resolved STANBOL-222.
-----------------------------------------

    Resolution: Fixed

Fixed with revision 1136059

Sorry forgot to mention this Issue in the commit

Here the related comments:

### FieldQuery to SPARQL

Based on the feedback provided by Andrea several improvements to the generated SPARQL queries where made (see http://markmail.org/thread/wxd4rdjcssi5b4u6 for details)

* Fixed a bug in the full text search optimization for Virtuoso that prevented results for queries containing spaces.
* The usage of SPARQL 1.1 sub-select should solve problems with LIMIT. Currently sub-selects are only supported by Virtuoso.
* OPTIONAL selects are now only selected for previously selected entities. This greatly improves performance in such cases


for details see: http://svn.apache.org/viewvc?rev=1136059&view=rev

> Timeout exception from LOD remote endpoints when performing queries with the Entity Hub.
> ----------------------------------------------------------------------------------------
>
>                 Key: STANBOL-222
>                 URL: https://issues.apache.org/jira/browse/STANBOL-222
>             Project: Stanbol
>          Issue Type: Bug
>          Components: Entity Hub
>            Reporter: Andrea Nuzzolese
>            Assignee: Rupert Westenthaler
>
> The sparql constructs serialized by the Entity Hub that is used for querying remote LOD endpoints contain OPTIONAL patterns that require too much time to be evaluated.
> An example is the following
> CONSTRUCT { ... }
> WHERE {     
> 	{ {?id <http://www.w3.org/2002/07/owl#sameAs> <http://www4.wiwiss.fu-berlin.de/factbook/resource/United_States> }}    
> 	 { OPTIONAL { ?id <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?v_1 . } }   
> 	 { OPTIONAL { ?id <http://www.w3.org/2000/01/rdf-schema#label> ?v_2 . } } 
> }  
> ...
> The sparql engine tries to satisfy the optional clauses in the whole graph ignoring the first condition ?id <http://www.w3.org/2002/07/owl#sameAs> <http://www4.wiwiss.fu-berlin.de/factbook/resource/United_States>

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[jira] [Assigned] (STANBOL-222) Timeout exception from LOD remote endpoints when performing queries with the Entity Hub.

Posted by "Rupert Westenthaler (JIRA)" <ji...@apache.org>.
     [ https://issues.apache.org/jira/browse/STANBOL-222?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Rupert Westenthaler reassigned STANBOL-222:
-------------------------------------------

    Assignee: Rupert Westenthaler

> Timeout exception from LOD remote endpoints when performing queries with the Entity Hub.
> ----------------------------------------------------------------------------------------
>
>                 Key: STANBOL-222
>                 URL: https://issues.apache.org/jira/browse/STANBOL-222
>             Project: Stanbol
>          Issue Type: Bug
>          Components: Entity Hub
>            Reporter: Andrea Nuzzolese
>            Assignee: Rupert Westenthaler
>
> The sparql constructs serialized by the Entity Hub that is used for querying remote LOD endpoints contain OPTIONAL patterns that require too much time to be evaluated.
> An example is the following
> CONSTRUCT { ... }
> WHERE {     
> 	{ {?id <http://www.w3.org/2002/07/owl#sameAs> <http://www4.wiwiss.fu-berlin.de/factbook/resource/United_States> }}    
> 	 { OPTIONAL { ?id <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> ?v_1 . } }   
> 	 { OPTIONAL { ?id <http://www.w3.org/2000/01/rdf-schema#label> ?v_2 . } } 
> }  
> ...
> The sparql engine tries to satisfy the optional clauses in the whole graph ignoring the first condition ?id <http://www.w3.org/2002/07/owl#sameAs> <http://www4.wiwiss.fu-berlin.de/factbook/resource/United_States>

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